Polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyester, and the like from petroleum are used for general plastic shrinkable films. Since these shrinkable films are chemically and biologically stable, they need a significantly long time to decompose, which causes serious environmental problems.
Currently, commonly used biodegradable shrinkable films are mainly made of polylactic acid, but since they have low shrinkage ratios and have brittle characteristics due to a crystallization phenomenon in a film manufacturing procedure, the uses thereof are limited. In order to improve the crystallization phenomenon, biodegradable aliphatic polyester having a glass transition temperature of 0° C. or lower is blended in the film manufacture procedure. However, the usability thereof is deteriorated to lead an increase in film opacity, resulting in limited uses thereof, and thermal characteristics of the resin blended itself leads to reduced productivity and the shrinkage ratios of final products are difficult to control, resulting in limited uses thereof.
In addition, since the other processes are not carried out in the manufacturing procedure of the final film, aluminum deposited after an aluminum deposition process for being used in food packaging and the like may be delaminated or separated, resulting in limited uses.